linux/fs/fat/inode.c
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   1/*
   2 *  linux/fs/fat/inode.c
   3 *
   4 *  Written 1992,1993 by Werner Almesberger
   5 *  VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner
   6 *  Rewritten for the constant inumbers support by Al Viro
   7 *
   8 *  Fixes:
   9 *
  10 *      Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
  11 */
  12
  13#include <linux/module.h>
  14#include <linux/init.h>
  15#include <linux/time.h>
  16#include <linux/slab.h>
  17#include <linux/seq_file.h>
  18#include <linux/pagemap.h>
  19#include <linux/mpage.h>
  20#include <linux/buffer_head.h>
  21#include <linux/mount.h>
  22#include <linux/aio.h>
  23#include <linux/vfs.h>
  24#include <linux/parser.h>
  25#include <linux/uio.h>
  26#include <linux/writeback.h>
  27#include <linux/log2.h>
  28#include <linux/hash.h>
  29#include <linux/blkdev.h>
  30#include <asm/unaligned.h>
  31#include "fat.h"
  32
  33#ifndef CONFIG_FAT_DEFAULT_IOCHARSET
  34/* if user don't select VFAT, this is undefined. */
  35#define CONFIG_FAT_DEFAULT_IOCHARSET    ""
  36#endif
  37
  38static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
  39static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
  40
  41
  42static int fat_add_cluster(struct inode *inode)
  43{
  44        int err, cluster;
  45
  46        err = fat_alloc_clusters(inode, &cluster, 1);
  47        if (err)
  48                return err;
  49        /* FIXME: this cluster should be added after data of this
  50         * cluster is writed */
  51        err = fat_chain_add(inode, cluster, 1);
  52        if (err)
  53                fat_free_clusters(inode, cluster);
  54        return err;
  55}
  56
  57static inline int __fat_get_block(struct inode *inode, sector_t iblock,
  58                                  unsigned long *max_blocks,
  59                                  struct buffer_head *bh_result, int create)
  60{
  61        struct super_block *sb = inode->i_sb;
  62        struct msdos_sb_info *sbi = MSDOS_SB(sb);
  63        unsigned long mapped_blocks;
  64        sector_t phys;
  65        int err, offset;
  66
  67        err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
  68        if (err)
  69                return err;
  70        if (phys) {
  71                map_bh(bh_result, sb, phys);
  72                *max_blocks = min(mapped_blocks, *max_blocks);
  73                return 0;
  74        }
  75        if (!create)
  76                return 0;
  77
  78        if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
  79                fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)",
  80                        MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
  81                return -EIO;
  82        }
  83
  84        offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
  85        if (!offset) {
  86                /* TODO: multiple cluster allocation would be desirable. */
  87                err = fat_add_cluster(inode);
  88                if (err)
  89                        return err;
  90        }
  91        /* available blocks on this cluster */
  92        mapped_blocks = sbi->sec_per_clus - offset;
  93
  94        *max_blocks = min(mapped_blocks, *max_blocks);
  95        MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
  96
  97        err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
  98        if (err)
  99                return err;
 100
 101        BUG_ON(!phys);
 102        BUG_ON(*max_blocks != mapped_blocks);
 103        set_buffer_new(bh_result);
 104        map_bh(bh_result, sb, phys);
 105
 106        return 0;
 107}
 108
 109static int fat_get_block(struct inode *inode, sector_t iblock,
 110                         struct buffer_head *bh_result, int create)
 111{
 112        struct super_block *sb = inode->i_sb;
 113        unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
 114        int err;
 115
 116        err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
 117        if (err)
 118                return err;
 119        bh_result->b_size = max_blocks << sb->s_blocksize_bits;
 120        return 0;
 121}
 122
 123static int fat_writepage(struct page *page, struct writeback_control *wbc)
 124{
 125        return block_write_full_page(page, fat_get_block, wbc);
 126}
 127
 128static int fat_writepages(struct address_space *mapping,
 129                          struct writeback_control *wbc)
 130{
 131        return mpage_writepages(mapping, wbc, fat_get_block);
 132}
 133
 134static int fat_readpage(struct file *file, struct page *page)
 135{
 136        return mpage_readpage(page, fat_get_block);
 137}
 138
 139static int fat_readpages(struct file *file, struct address_space *mapping,
 140                         struct list_head *pages, unsigned nr_pages)
 141{
 142        return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
 143}
 144
 145static void fat_write_failed(struct address_space *mapping, loff_t to)
 146{
 147        struct inode *inode = mapping->host;
 148
 149        if (to > inode->i_size) {
 150                truncate_pagecache(inode, to, inode->i_size);
 151                fat_truncate_blocks(inode, inode->i_size);
 152        }
 153}
 154
 155static int fat_write_begin(struct file *file, struct address_space *mapping,
 156                        loff_t pos, unsigned len, unsigned flags,
 157                        struct page **pagep, void **fsdata)
 158{
 159        int err;
 160
 161        *pagep = NULL;
 162        err = cont_write_begin(file, mapping, pos, len, flags,
 163                                pagep, fsdata, fat_get_block,
 164                                &MSDOS_I(mapping->host)->mmu_private);
 165        if (err < 0)
 166                fat_write_failed(mapping, pos + len);
 167        return err;
 168}
 169
 170static int fat_write_end(struct file *file, struct address_space *mapping,
 171                        loff_t pos, unsigned len, unsigned copied,
 172                        struct page *pagep, void *fsdata)
 173{
 174        struct inode *inode = mapping->host;
 175        int err;
 176        err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
 177        if (err < len)
 178                fat_write_failed(mapping, pos + len);
 179        if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
 180                inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
 181                MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
 182                mark_inode_dirty(inode);
 183        }
 184        return err;
 185}
 186
 187static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
 188                             const struct iovec *iov,
 189                             loff_t offset, unsigned long nr_segs)
 190{
 191        struct file *file = iocb->ki_filp;
 192        struct address_space *mapping = file->f_mapping;
 193        struct inode *inode = mapping->host;
 194        ssize_t ret;
 195
 196        if (rw == WRITE) {
 197                /*
 198                 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
 199                 * so we need to update the ->mmu_private to block boundary.
 200                 *
 201                 * But we must fill the remaining area or hole by nul for
 202                 * updating ->mmu_private.
 203                 *
 204                 * Return 0, and fallback to normal buffered write.
 205                 */
 206                loff_t size = offset + iov_length(iov, nr_segs);
 207                if (MSDOS_I(inode)->mmu_private < size)
 208                        return 0;
 209        }
 210
 211        /*
 212         * FAT need to use the DIO_LOCKING for avoiding the race
 213         * condition of fat_get_block() and ->truncate().
 214         */
 215        ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
 216                                 fat_get_block);
 217        if (ret < 0 && (rw & WRITE))
 218                fat_write_failed(mapping, offset + iov_length(iov, nr_segs));
 219
 220        return ret;
 221}
 222
 223static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
 224{
 225        sector_t blocknr;
 226
 227        /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
 228        down_read(&MSDOS_I(mapping->host)->truncate_lock);
 229        blocknr = generic_block_bmap(mapping, block, fat_get_block);
 230        up_read(&MSDOS_I(mapping->host)->truncate_lock);
 231
 232        return blocknr;
 233}
 234
 235static const struct address_space_operations fat_aops = {
 236        .readpage       = fat_readpage,
 237        .readpages      = fat_readpages,
 238        .writepage      = fat_writepage,
 239        .writepages     = fat_writepages,
 240        .write_begin    = fat_write_begin,
 241        .write_end      = fat_write_end,
 242        .direct_IO      = fat_direct_IO,
 243        .bmap           = _fat_bmap
 244};
 245
 246/*
 247 * New FAT inode stuff. We do the following:
 248 *      a) i_ino is constant and has nothing with on-disk location.
 249 *      b) FAT manages its own cache of directory entries.
 250 *      c) *This* cache is indexed by on-disk location.
 251 *      d) inode has an associated directory entry, all right, but
 252 *              it may be unhashed.
 253 *      e) currently entries are stored within struct inode. That should
 254 *              change.
 255 *      f) we deal with races in the following way:
 256 *              1. readdir() and lookup() do FAT-dir-cache lookup.
 257 *              2. rename() unhashes the F-d-c entry and rehashes it in
 258 *                      a new place.
 259 *              3. unlink() and rmdir() unhash F-d-c entry.
 260 *              4. fat_write_inode() checks whether the thing is unhashed.
 261 *                      If it is we silently return. If it isn't we do bread(),
 262 *                      check if the location is still valid and retry if it
 263 *                      isn't. Otherwise we do changes.
 264 *              5. Spinlock is used to protect hash/unhash/location check/lookup
 265 *              6. fat_evict_inode() unhashes the F-d-c entry.
 266 *              7. lookup() and readdir() do igrab() if they find a F-d-c entry
 267 *                      and consider negative result as cache miss.
 268 */
 269
 270static void fat_hash_init(struct super_block *sb)
 271{
 272        struct msdos_sb_info *sbi = MSDOS_SB(sb);
 273        int i;
 274
 275        spin_lock_init(&sbi->inode_hash_lock);
 276        for (i = 0; i < FAT_HASH_SIZE; i++)
 277                INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
 278}
 279
 280static inline unsigned long fat_hash(loff_t i_pos)
 281{
 282        return hash_32(i_pos, FAT_HASH_BITS);
 283}
 284
 285static void dir_hash_init(struct super_block *sb)
 286{
 287        struct msdos_sb_info *sbi = MSDOS_SB(sb);
 288        int i;
 289
 290        spin_lock_init(&sbi->dir_hash_lock);
 291        for (i = 0; i < FAT_HASH_SIZE; i++)
 292                INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
 293}
 294
 295void fat_attach(struct inode *inode, loff_t i_pos)
 296{
 297        struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 298
 299        if (inode->i_ino != MSDOS_ROOT_INO) {
 300                struct hlist_head *head =   sbi->inode_hashtable
 301                                          + fat_hash(i_pos);
 302
 303                spin_lock(&sbi->inode_hash_lock);
 304                MSDOS_I(inode)->i_pos = i_pos;
 305                hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
 306                spin_unlock(&sbi->inode_hash_lock);
 307        }
 308
 309        /* If NFS support is enabled, cache the mapping of start cluster
 310         * to directory inode. This is used during reconnection of
 311         * dentries to the filesystem root.
 312         */
 313        if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
 314                struct hlist_head *d_head = sbi->dir_hashtable;
 315                d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
 316
 317                spin_lock(&sbi->dir_hash_lock);
 318                hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
 319                spin_unlock(&sbi->dir_hash_lock);
 320        }
 321}
 322EXPORT_SYMBOL_GPL(fat_attach);
 323
 324void fat_detach(struct inode *inode)
 325{
 326        struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 327        spin_lock(&sbi->inode_hash_lock);
 328        MSDOS_I(inode)->i_pos = 0;
 329        hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
 330        spin_unlock(&sbi->inode_hash_lock);
 331
 332        if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
 333                spin_lock(&sbi->dir_hash_lock);
 334                hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
 335                spin_unlock(&sbi->dir_hash_lock);
 336        }
 337}
 338EXPORT_SYMBOL_GPL(fat_detach);
 339
 340struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
 341{
 342        struct msdos_sb_info *sbi = MSDOS_SB(sb);
 343        struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
 344        struct msdos_inode_info *i;
 345        struct inode *inode = NULL;
 346
 347        spin_lock(&sbi->inode_hash_lock);
 348        hlist_for_each_entry(i, head, i_fat_hash) {
 349                BUG_ON(i->vfs_inode.i_sb != sb);
 350                if (i->i_pos != i_pos)
 351                        continue;
 352                inode = igrab(&i->vfs_inode);
 353                if (inode)
 354                        break;
 355        }
 356        spin_unlock(&sbi->inode_hash_lock);
 357        return inode;
 358}
 359
 360static int is_exec(unsigned char *extension)
 361{
 362        unsigned char *exe_extensions = "EXECOMBAT", *walk;
 363
 364        for (walk = exe_extensions; *walk; walk += 3)
 365                if (!strncmp(extension, walk, 3))
 366                        return 1;
 367        return 0;
 368}
 369
 370static int fat_calc_dir_size(struct inode *inode)
 371{
 372        struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 373        int ret, fclus, dclus;
 374
 375        inode->i_size = 0;
 376        if (MSDOS_I(inode)->i_start == 0)
 377                return 0;
 378
 379        ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
 380        if (ret < 0)
 381                return ret;
 382        inode->i_size = (fclus + 1) << sbi->cluster_bits;
 383
 384        return 0;
 385}
 386
 387/* doesn't deal with root inode */
 388int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
 389{
 390        struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 391        int error;
 392
 393        MSDOS_I(inode)->i_pos = 0;
 394        inode->i_uid = sbi->options.fs_uid;
 395        inode->i_gid = sbi->options.fs_gid;
 396        inode->i_version++;
 397        inode->i_generation = get_seconds();
 398
 399        if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
 400                inode->i_generation &= ~1;
 401                inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
 402                inode->i_op = sbi->dir_ops;
 403                inode->i_fop = &fat_dir_operations;
 404
 405                MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
 406                MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
 407                error = fat_calc_dir_size(inode);
 408                if (error < 0)
 409                        return error;
 410                MSDOS_I(inode)->mmu_private = inode->i_size;
 411
 412                set_nlink(inode, fat_subdirs(inode));
 413        } else { /* not a directory */
 414                inode->i_generation |= 1;
 415                inode->i_mode = fat_make_mode(sbi, de->attr,
 416                        ((sbi->options.showexec && !is_exec(de->name + 8))
 417                         ? S_IRUGO|S_IWUGO : S_IRWXUGO));
 418                MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
 419
 420                MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
 421                inode->i_size = le32_to_cpu(de->size);
 422                inode->i_op = &fat_file_inode_operations;
 423                inode->i_fop = &fat_file_operations;
 424                inode->i_mapping->a_ops = &fat_aops;
 425                MSDOS_I(inode)->mmu_private = inode->i_size;
 426        }
 427        if (de->attr & ATTR_SYS) {
 428                if (sbi->options.sys_immutable)
 429                        inode->i_flags |= S_IMMUTABLE;
 430        }
 431        fat_save_attrs(inode, de->attr);
 432
 433        inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
 434                           & ~((loff_t)sbi->cluster_size - 1)) >> 9;
 435
 436        fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
 437        if (sbi->options.isvfat) {
 438                fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
 439                                  de->cdate, de->ctime_cs);
 440                fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
 441        } else
 442                inode->i_ctime = inode->i_atime = inode->i_mtime;
 443
 444        return 0;
 445}
 446
 447static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
 448{
 449        if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
 450                mutex_lock(&sbi->nfs_build_inode_lock);
 451}
 452
 453static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
 454{
 455        if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
 456                mutex_unlock(&sbi->nfs_build_inode_lock);
 457}
 458
 459struct inode *fat_build_inode(struct super_block *sb,
 460                        struct msdos_dir_entry *de, loff_t i_pos)
 461{
 462        struct inode *inode;
 463        int err;
 464
 465        fat_lock_build_inode(MSDOS_SB(sb));
 466        inode = fat_iget(sb, i_pos);
 467        if (inode)
 468                goto out;
 469        inode = new_inode(sb);
 470        if (!inode) {
 471                inode = ERR_PTR(-ENOMEM);
 472                goto out;
 473        }
 474        inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
 475        inode->i_version = 1;
 476        err = fat_fill_inode(inode, de);
 477        if (err) {
 478                iput(inode);
 479                inode = ERR_PTR(err);
 480                goto out;
 481        }
 482        fat_attach(inode, i_pos);
 483        insert_inode_hash(inode);
 484out:
 485        fat_unlock_build_inode(MSDOS_SB(sb));
 486        return inode;
 487}
 488
 489EXPORT_SYMBOL_GPL(fat_build_inode);
 490
 491static void fat_evict_inode(struct inode *inode)
 492{
 493        truncate_inode_pages(&inode->i_data, 0);
 494        if (!inode->i_nlink) {
 495                inode->i_size = 0;
 496                fat_truncate_blocks(inode, 0);
 497        }
 498        invalidate_inode_buffers(inode);
 499        clear_inode(inode);
 500        fat_cache_inval_inode(inode);
 501        fat_detach(inode);
 502}
 503
 504static void fat_set_state(struct super_block *sb,
 505                        unsigned int set, unsigned int force)
 506{
 507        struct buffer_head *bh;
 508        struct fat_boot_sector *b;
 509        struct msdos_sb_info *sbi = sb->s_fs_info;
 510
 511        /* do not change any thing if mounted read only */
 512        if ((sb->s_flags & MS_RDONLY) && !force)
 513                return;
 514
 515        /* do not change state if fs was dirty */
 516        if (sbi->dirty) {
 517                /* warn only on set (mount). */
 518                if (set)
 519                        fat_msg(sb, KERN_WARNING, "Volume was not properly "
 520                                "unmounted. Some data may be corrupt. "
 521                                "Please run fsck.");
 522                return;
 523        }
 524
 525        bh = sb_bread(sb, 0);
 526        if (bh == NULL) {
 527                fat_msg(sb, KERN_ERR, "unable to read boot sector "
 528                        "to mark fs as dirty");
 529                return;
 530        }
 531
 532        b = (struct fat_boot_sector *) bh->b_data;
 533
 534        if (sbi->fat_bits == 32) {
 535                if (set)
 536                        b->fat32.state |= FAT_STATE_DIRTY;
 537                else
 538                        b->fat32.state &= ~FAT_STATE_DIRTY;
 539        } else /* fat 16 and 12 */ {
 540                if (set)
 541                        b->fat16.state |= FAT_STATE_DIRTY;
 542                else
 543                        b->fat16.state &= ~FAT_STATE_DIRTY;
 544        }
 545
 546        mark_buffer_dirty(bh);
 547        sync_dirty_buffer(bh);
 548        brelse(bh);
 549}
 550
 551static void fat_put_super(struct super_block *sb)
 552{
 553        struct msdos_sb_info *sbi = MSDOS_SB(sb);
 554
 555        fat_set_state(sb, 0, 0);
 556
 557        iput(sbi->fsinfo_inode);
 558        iput(sbi->fat_inode);
 559
 560        unload_nls(sbi->nls_disk);
 561        unload_nls(sbi->nls_io);
 562
 563        if (sbi->options.iocharset != fat_default_iocharset)
 564                kfree(sbi->options.iocharset);
 565
 566        sb->s_fs_info = NULL;
 567        kfree(sbi);
 568}
 569
 570static struct kmem_cache *fat_inode_cachep;
 571
 572static struct inode *fat_alloc_inode(struct super_block *sb)
 573{
 574        struct msdos_inode_info *ei;
 575        ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
 576        if (!ei)
 577                return NULL;
 578
 579        init_rwsem(&ei->truncate_lock);
 580        return &ei->vfs_inode;
 581}
 582
 583static void fat_i_callback(struct rcu_head *head)
 584{
 585        struct inode *inode = container_of(head, struct inode, i_rcu);
 586        kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
 587}
 588
 589static void fat_destroy_inode(struct inode *inode)
 590{
 591        call_rcu(&inode->i_rcu, fat_i_callback);
 592}
 593
 594static void init_once(void *foo)
 595{
 596        struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
 597
 598        spin_lock_init(&ei->cache_lru_lock);
 599        ei->nr_caches = 0;
 600        ei->cache_valid_id = FAT_CACHE_VALID + 1;
 601        INIT_LIST_HEAD(&ei->cache_lru);
 602        INIT_HLIST_NODE(&ei->i_fat_hash);
 603        INIT_HLIST_NODE(&ei->i_dir_hash);
 604        inode_init_once(&ei->vfs_inode);
 605}
 606
 607static int __init fat_init_inodecache(void)
 608{
 609        fat_inode_cachep = kmem_cache_create("fat_inode_cache",
 610                                             sizeof(struct msdos_inode_info),
 611                                             0, (SLAB_RECLAIM_ACCOUNT|
 612                                                SLAB_MEM_SPREAD),
 613                                             init_once);
 614        if (fat_inode_cachep == NULL)
 615                return -ENOMEM;
 616        return 0;
 617}
 618
 619static void __exit fat_destroy_inodecache(void)
 620{
 621        /*
 622         * Make sure all delayed rcu free inodes are flushed before we
 623         * destroy cache.
 624         */
 625        rcu_barrier();
 626        kmem_cache_destroy(fat_inode_cachep);
 627}
 628
 629static int fat_remount(struct super_block *sb, int *flags, char *data)
 630{
 631        int new_rdonly;
 632        struct msdos_sb_info *sbi = MSDOS_SB(sb);
 633        *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
 634
 635        /* make sure we update state on remount. */
 636        new_rdonly = *flags & MS_RDONLY;
 637        if (new_rdonly != (sb->s_flags & MS_RDONLY)) {
 638                if (new_rdonly)
 639                        fat_set_state(sb, 0, 0);
 640                else
 641                        fat_set_state(sb, 1, 1);
 642        }
 643        return 0;
 644}
 645
 646static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
 647{
 648        struct super_block *sb = dentry->d_sb;
 649        struct msdos_sb_info *sbi = MSDOS_SB(sb);
 650        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 651
 652        /* If the count of free cluster is still unknown, counts it here. */
 653        if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
 654                int err = fat_count_free_clusters(dentry->d_sb);
 655                if (err)
 656                        return err;
 657        }
 658
 659        buf->f_type = dentry->d_sb->s_magic;
 660        buf->f_bsize = sbi->cluster_size;
 661        buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
 662        buf->f_bfree = sbi->free_clusters;
 663        buf->f_bavail = sbi->free_clusters;
 664        buf->f_fsid.val[0] = (u32)id;
 665        buf->f_fsid.val[1] = (u32)(id >> 32);
 666        buf->f_namelen =
 667                (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
 668
 669        return 0;
 670}
 671
 672static int __fat_write_inode(struct inode *inode, int wait)
 673{
 674        struct super_block *sb = inode->i_sb;
 675        struct msdos_sb_info *sbi = MSDOS_SB(sb);
 676        struct buffer_head *bh;
 677        struct msdos_dir_entry *raw_entry;
 678        loff_t i_pos;
 679        sector_t blocknr;
 680        int err, offset;
 681
 682        if (inode->i_ino == MSDOS_ROOT_INO)
 683                return 0;
 684
 685retry:
 686        i_pos = fat_i_pos_read(sbi, inode);
 687        if (!i_pos)
 688                return 0;
 689
 690        fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
 691        bh = sb_bread(sb, blocknr);
 692        if (!bh) {
 693                fat_msg(sb, KERN_ERR, "unable to read inode block "
 694                       "for updating (i_pos %lld)", i_pos);
 695                return -EIO;
 696        }
 697        spin_lock(&sbi->inode_hash_lock);
 698        if (i_pos != MSDOS_I(inode)->i_pos) {
 699                spin_unlock(&sbi->inode_hash_lock);
 700                brelse(bh);
 701                goto retry;
 702        }
 703
 704        raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
 705        if (S_ISDIR(inode->i_mode))
 706                raw_entry->size = 0;
 707        else
 708                raw_entry->size = cpu_to_le32(inode->i_size);
 709        raw_entry->attr = fat_make_attrs(inode);
 710        fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
 711        fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
 712                          &raw_entry->date, NULL);
 713        if (sbi->options.isvfat) {
 714                __le16 atime;
 715                fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
 716                                  &raw_entry->cdate, &raw_entry->ctime_cs);
 717                fat_time_unix2fat(sbi, &inode->i_atime, &atime,
 718                                  &raw_entry->adate, NULL);
 719        }
 720        spin_unlock(&sbi->inode_hash_lock);
 721        mark_buffer_dirty(bh);
 722        err = 0;
 723        if (wait)
 724                err = sync_dirty_buffer(bh);
 725        brelse(bh);
 726        return err;
 727}
 728
 729static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
 730{
 731        int err;
 732
 733        if (inode->i_ino == MSDOS_FSINFO_INO) {
 734                struct super_block *sb = inode->i_sb;
 735
 736                mutex_lock(&MSDOS_SB(sb)->s_lock);
 737                err = fat_clusters_flush(sb);
 738                mutex_unlock(&MSDOS_SB(sb)->s_lock);
 739        } else
 740                err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
 741
 742        return err;
 743}
 744
 745int fat_sync_inode(struct inode *inode)
 746{
 747        return __fat_write_inode(inode, 1);
 748}
 749
 750EXPORT_SYMBOL_GPL(fat_sync_inode);
 751
 752static int fat_show_options(struct seq_file *m, struct dentry *root);
 753static const struct super_operations fat_sops = {
 754        .alloc_inode    = fat_alloc_inode,
 755        .destroy_inode  = fat_destroy_inode,
 756        .write_inode    = fat_write_inode,
 757        .evict_inode    = fat_evict_inode,
 758        .put_super      = fat_put_super,
 759        .statfs         = fat_statfs,
 760        .remount_fs     = fat_remount,
 761
 762        .show_options   = fat_show_options,
 763};
 764
 765static int fat_show_options(struct seq_file *m, struct dentry *root)
 766{
 767        struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
 768        struct fat_mount_options *opts = &sbi->options;
 769        int isvfat = opts->isvfat;
 770
 771        if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
 772                seq_printf(m, ",uid=%u",
 773                                from_kuid_munged(&init_user_ns, opts->fs_uid));
 774        if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
 775                seq_printf(m, ",gid=%u",
 776                                from_kgid_munged(&init_user_ns, opts->fs_gid));
 777        seq_printf(m, ",fmask=%04o", opts->fs_fmask);
 778        seq_printf(m, ",dmask=%04o", opts->fs_dmask);
 779        if (opts->allow_utime)
 780                seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
 781        if (sbi->nls_disk)
 782                /* strip "cp" prefix from displayed option */
 783                seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
 784        if (isvfat) {
 785                if (sbi->nls_io)
 786                        seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
 787
 788                switch (opts->shortname) {
 789                case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
 790                        seq_puts(m, ",shortname=win95");
 791                        break;
 792                case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
 793                        seq_puts(m, ",shortname=winnt");
 794                        break;
 795                case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
 796                        seq_puts(m, ",shortname=mixed");
 797                        break;
 798                case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
 799                        seq_puts(m, ",shortname=lower");
 800                        break;
 801                default:
 802                        seq_puts(m, ",shortname=unknown");
 803                        break;
 804                }
 805        }
 806        if (opts->name_check != 'n')
 807                seq_printf(m, ",check=%c", opts->name_check);
 808        if (opts->usefree)
 809                seq_puts(m, ",usefree");
 810        if (opts->quiet)
 811                seq_puts(m, ",quiet");
 812        if (opts->showexec)
 813                seq_puts(m, ",showexec");
 814        if (opts->sys_immutable)
 815                seq_puts(m, ",sys_immutable");
 816        if (!isvfat) {
 817                if (opts->dotsOK)
 818                        seq_puts(m, ",dotsOK=yes");
 819                if (opts->nocase)
 820                        seq_puts(m, ",nocase");
 821        } else {
 822                if (opts->utf8)
 823                        seq_puts(m, ",utf8");
 824                if (opts->unicode_xlate)
 825                        seq_puts(m, ",uni_xlate");
 826                if (!opts->numtail)
 827                        seq_puts(m, ",nonumtail");
 828                if (opts->rodir)
 829                        seq_puts(m, ",rodir");
 830        }
 831        if (opts->flush)
 832                seq_puts(m, ",flush");
 833        if (opts->tz_set) {
 834                if (opts->time_offset)
 835                        seq_printf(m, ",time_offset=%d", opts->time_offset);
 836                else
 837                        seq_puts(m, ",tz=UTC");
 838        }
 839        if (opts->errors == FAT_ERRORS_CONT)
 840                seq_puts(m, ",errors=continue");
 841        else if (opts->errors == FAT_ERRORS_PANIC)
 842                seq_puts(m, ",errors=panic");
 843        else
 844                seq_puts(m, ",errors=remount-ro");
 845        if (opts->nfs == FAT_NFS_NOSTALE_RO)
 846                seq_puts(m, ",nfs=nostale_ro");
 847        else if (opts->nfs)
 848                seq_puts(m, ",nfs=stale_rw");
 849        if (opts->discard)
 850                seq_puts(m, ",discard");
 851
 852        return 0;
 853}
 854
 855enum {
 856        Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
 857        Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
 858        Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
 859        Opt_immutable, Opt_dots, Opt_nodots,
 860        Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
 861        Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
 862        Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
 863        Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
 864        Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
 865        Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err,
 866};
 867
 868static const match_table_t fat_tokens = {
 869        {Opt_check_r, "check=relaxed"},
 870        {Opt_check_s, "check=strict"},
 871        {Opt_check_n, "check=normal"},
 872        {Opt_check_r, "check=r"},
 873        {Opt_check_s, "check=s"},
 874        {Opt_check_n, "check=n"},
 875        {Opt_uid, "uid=%u"},
 876        {Opt_gid, "gid=%u"},
 877        {Opt_umask, "umask=%o"},
 878        {Opt_dmask, "dmask=%o"},
 879        {Opt_fmask, "fmask=%o"},
 880        {Opt_allow_utime, "allow_utime=%o"},
 881        {Opt_codepage, "codepage=%u"},
 882        {Opt_usefree, "usefree"},
 883        {Opt_nocase, "nocase"},
 884        {Opt_quiet, "quiet"},
 885        {Opt_showexec, "showexec"},
 886        {Opt_debug, "debug"},
 887        {Opt_immutable, "sys_immutable"},
 888        {Opt_flush, "flush"},
 889        {Opt_tz_utc, "tz=UTC"},
 890        {Opt_time_offset, "time_offset=%d"},
 891        {Opt_err_cont, "errors=continue"},
 892        {Opt_err_panic, "errors=panic"},
 893        {Opt_err_ro, "errors=remount-ro"},
 894        {Opt_discard, "discard"},
 895        {Opt_nfs_stale_rw, "nfs"},
 896        {Opt_nfs_stale_rw, "nfs=stale_rw"},
 897        {Opt_nfs_nostale_ro, "nfs=nostale_ro"},
 898        {Opt_obsolete, "conv=binary"},
 899        {Opt_obsolete, "conv=text"},
 900        {Opt_obsolete, "conv=auto"},
 901        {Opt_obsolete, "conv=b"},
 902        {Opt_obsolete, "conv=t"},
 903        {Opt_obsolete, "conv=a"},
 904        {Opt_obsolete, "fat=%u"},
 905        {Opt_obsolete, "blocksize=%u"},
 906        {Opt_obsolete, "cvf_format=%20s"},
 907        {Opt_obsolete, "cvf_options=%100s"},
 908        {Opt_obsolete, "posix"},
 909        {Opt_err, NULL},
 910};
 911static const match_table_t msdos_tokens = {
 912        {Opt_nodots, "nodots"},
 913        {Opt_nodots, "dotsOK=no"},
 914        {Opt_dots, "dots"},
 915        {Opt_dots, "dotsOK=yes"},
 916        {Opt_err, NULL}
 917};
 918static const match_table_t vfat_tokens = {
 919        {Opt_charset, "iocharset=%s"},
 920        {Opt_shortname_lower, "shortname=lower"},
 921        {Opt_shortname_win95, "shortname=win95"},
 922        {Opt_shortname_winnt, "shortname=winnt"},
 923        {Opt_shortname_mixed, "shortname=mixed"},
 924        {Opt_utf8_no, "utf8=0"},                /* 0 or no or false */
 925        {Opt_utf8_no, "utf8=no"},
 926        {Opt_utf8_no, "utf8=false"},
 927        {Opt_utf8_yes, "utf8=1"},               /* empty or 1 or yes or true */
 928        {Opt_utf8_yes, "utf8=yes"},
 929        {Opt_utf8_yes, "utf8=true"},
 930        {Opt_utf8_yes, "utf8"},
 931        {Opt_uni_xl_no, "uni_xlate=0"},         /* 0 or no or false */
 932        {Opt_uni_xl_no, "uni_xlate=no"},
 933        {Opt_uni_xl_no, "uni_xlate=false"},
 934        {Opt_uni_xl_yes, "uni_xlate=1"},        /* empty or 1 or yes or true */
 935        {Opt_uni_xl_yes, "uni_xlate=yes"},
 936        {Opt_uni_xl_yes, "uni_xlate=true"},
 937        {Opt_uni_xl_yes, "uni_xlate"},
 938        {Opt_nonumtail_no, "nonumtail=0"},      /* 0 or no or false */
 939        {Opt_nonumtail_no, "nonumtail=no"},
 940        {Opt_nonumtail_no, "nonumtail=false"},
 941        {Opt_nonumtail_yes, "nonumtail=1"},     /* empty or 1 or yes or true */
 942        {Opt_nonumtail_yes, "nonumtail=yes"},
 943        {Opt_nonumtail_yes, "nonumtail=true"},
 944        {Opt_nonumtail_yes, "nonumtail"},
 945        {Opt_rodir, "rodir"},
 946        {Opt_err, NULL}
 947};
 948
 949static int parse_options(struct super_block *sb, char *options, int is_vfat,
 950                         int silent, int *debug, struct fat_mount_options *opts)
 951{
 952        char *p;
 953        substring_t args[MAX_OPT_ARGS];
 954        int option;
 955        char *iocharset;
 956
 957        opts->isvfat = is_vfat;
 958
 959        opts->fs_uid = current_uid();
 960        opts->fs_gid = current_gid();
 961        opts->fs_fmask = opts->fs_dmask = current_umask();
 962        opts->allow_utime = -1;
 963        opts->codepage = fat_default_codepage;
 964        opts->iocharset = fat_default_iocharset;
 965        if (is_vfat) {
 966                opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
 967                opts->rodir = 0;
 968        } else {
 969                opts->shortname = 0;
 970                opts->rodir = 1;
 971        }
 972        opts->name_check = 'n';
 973        opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK =  0;
 974        opts->utf8 = opts->unicode_xlate = 0;
 975        opts->numtail = 1;
 976        opts->usefree = opts->nocase = 0;
 977        opts->tz_set = 0;
 978        opts->nfs = 0;
 979        opts->errors = FAT_ERRORS_RO;
 980        *debug = 0;
 981
 982        if (!options)
 983                goto out;
 984
 985        while ((p = strsep(&options, ",")) != NULL) {
 986                int token;
 987                if (!*p)
 988                        continue;
 989
 990                token = match_token(p, fat_tokens, args);
 991                if (token == Opt_err) {
 992                        if (is_vfat)
 993                                token = match_token(p, vfat_tokens, args);
 994                        else
 995                                token = match_token(p, msdos_tokens, args);
 996                }
 997                switch (token) {
 998                case Opt_check_s:
 999                        opts->name_check = 's';
1000                        break;
1001                case Opt_check_r:
1002                        opts->name_check = 'r';
1003                        break;
1004                case Opt_check_n:
1005                        opts->name_check = 'n';
1006                        break;
1007                case Opt_usefree:
1008                        opts->usefree = 1;
1009                        break;
1010                case Opt_nocase:
1011                        if (!is_vfat)
1012                                opts->nocase = 1;
1013                        else {
1014                                /* for backward compatibility */
1015                                opts->shortname = VFAT_SFN_DISPLAY_WIN95
1016                                        | VFAT_SFN_CREATE_WIN95;
1017                        }
1018                        break;
1019                case Opt_quiet:
1020                        opts->quiet = 1;
1021                        break;
1022                case Opt_showexec:
1023                        opts->showexec = 1;
1024                        break;
1025                case Opt_debug:
1026                        *debug = 1;
1027                        break;
1028                case Opt_immutable:
1029                        opts->sys_immutable = 1;
1030                        break;
1031                case Opt_uid:
1032                        if (match_int(&args[0], &option))
1033                                return -EINVAL;
1034                        opts->fs_uid = make_kuid(current_user_ns(), option);
1035                        if (!uid_valid(opts->fs_uid))
1036                                return -EINVAL;
1037                        break;
1038                case Opt_gid:
1039                        if (match_int(&args[0], &option))
1040                                return -EINVAL;
1041                        opts->fs_gid = make_kgid(current_user_ns(), option);
1042                        if (!gid_valid(opts->fs_gid))
1043                                return -EINVAL;
1044                        break;
1045                case Opt_umask:
1046                        if (match_octal(&args[0], &option))
1047                                return -EINVAL;
1048                        opts->fs_fmask = opts->fs_dmask = option;
1049                        break;
1050                case Opt_dmask:
1051                        if (match_octal(&args[0], &option))
1052                                return -EINVAL;
1053                        opts->fs_dmask = option;
1054                        break;
1055                case Opt_fmask:
1056                        if (match_octal(&args[0], &option))
1057                                return -EINVAL;
1058                        opts->fs_fmask = option;
1059                        break;
1060                case Opt_allow_utime:
1061                        if (match_octal(&args[0], &option))
1062                                return -EINVAL;
1063                        opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1064                        break;
1065                case Opt_codepage:
1066                        if (match_int(&args[0], &option))
1067                                return -EINVAL;
1068                        opts->codepage = option;
1069                        break;
1070                case Opt_flush:
1071                        opts->flush = 1;
1072                        break;
1073                case Opt_time_offset:
1074                        if (match_int(&args[0], &option))
1075                                return -EINVAL;
1076                        if (option < -12 * 60 || option > 12 * 60)
1077                                return -EINVAL;
1078                        opts->tz_set = 1;
1079                        opts->time_offset = option;
1080                        break;
1081                case Opt_tz_utc:
1082                        opts->tz_set = 1;
1083                        opts->time_offset = 0;
1084                        break;
1085                case Opt_err_cont:
1086                        opts->errors = FAT_ERRORS_CONT;
1087                        break;
1088                case Opt_err_panic:
1089                        opts->errors = FAT_ERRORS_PANIC;
1090                        break;
1091                case Opt_err_ro:
1092                        opts->errors = FAT_ERRORS_RO;
1093                        break;
1094                case Opt_nfs_stale_rw:
1095                        opts->nfs = FAT_NFS_STALE_RW;
1096                        break;
1097                case Opt_nfs_nostale_ro:
1098                        opts->nfs = FAT_NFS_NOSTALE_RO;
1099                        break;
1100
1101                /* msdos specific */
1102                case Opt_dots:
1103                        opts->dotsOK = 1;
1104                        break;
1105                case Opt_nodots:
1106                        opts->dotsOK = 0;
1107                        break;
1108
1109                /* vfat specific */
1110                case Opt_charset:
1111                        if (opts->iocharset != fat_default_iocharset)
1112                                kfree(opts->iocharset);
1113                        iocharset = match_strdup(&args[0]);
1114                        if (!iocharset)
1115                                return -ENOMEM;
1116                        opts->iocharset = iocharset;
1117                        break;
1118                case Opt_shortname_lower:
1119                        opts->shortname = VFAT_SFN_DISPLAY_LOWER
1120                                        | VFAT_SFN_CREATE_WIN95;
1121                        break;
1122                case Opt_shortname_win95:
1123                        opts->shortname = VFAT_SFN_DISPLAY_WIN95
1124                                        | VFAT_SFN_CREATE_WIN95;
1125                        break;
1126                case Opt_shortname_winnt:
1127                        opts->shortname = VFAT_SFN_DISPLAY_WINNT
1128                                        | VFAT_SFN_CREATE_WINNT;
1129                        break;
1130                case Opt_shortname_mixed:
1131                        opts->shortname = VFAT_SFN_DISPLAY_WINNT
1132                                        | VFAT_SFN_CREATE_WIN95;
1133                        break;
1134                case Opt_utf8_no:               /* 0 or no or false */
1135                        opts->utf8 = 0;
1136                        break;
1137                case Opt_utf8_yes:              /* empty or 1 or yes or true */
1138                        opts->utf8 = 1;
1139                        break;
1140                case Opt_uni_xl_no:             /* 0 or no or false */
1141                        opts->unicode_xlate = 0;
1142                        break;
1143                case Opt_uni_xl_yes:            /* empty or 1 or yes or true */
1144                        opts->unicode_xlate = 1;
1145                        break;
1146                case Opt_nonumtail_no:          /* 0 or no or false */
1147                        opts->numtail = 1;      /* negated option */
1148                        break;
1149                case Opt_nonumtail_yes:         /* empty or 1 or yes or true */
1150                        opts->numtail = 0;      /* negated option */
1151                        break;
1152                case Opt_rodir:
1153                        opts->rodir = 1;
1154                        break;
1155                case Opt_discard:
1156                        opts->discard = 1;
1157                        break;
1158
1159                /* obsolete mount options */
1160                case Opt_obsolete:
1161                        fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
1162                               "not supported now", p);
1163                        break;
1164                /* unknown option */
1165                default:
1166                        if (!silent) {
1167                                fat_msg(sb, KERN_ERR,
1168                                       "Unrecognized mount option \"%s\" "
1169                                       "or missing value", p);
1170                        }
1171                        return -EINVAL;
1172                }
1173        }
1174
1175out:
1176        /* UTF-8 doesn't provide FAT semantics */
1177        if (!strcmp(opts->iocharset, "utf8")) {
1178                fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
1179                       " for FAT filesystems, filesystem will be "
1180                       "case sensitive!");
1181        }
1182
1183        /* If user doesn't specify allow_utime, it's initialized from dmask. */
1184        if (opts->allow_utime == (unsigned short)-1)
1185                opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1186        if (opts->unicode_xlate)
1187                opts->utf8 = 0;
1188        if (opts->nfs == FAT_NFS_NOSTALE_RO) {
1189                sb->s_flags |= MS_RDONLY;
1190                sb->s_export_op = &fat_export_ops_nostale;
1191        }
1192
1193        return 0;
1194}
1195
1196static int fat_read_root(struct inode *inode)
1197{
1198        struct super_block *sb = inode->i_sb;
1199        struct msdos_sb_info *sbi = MSDOS_SB(sb);
1200        int error;
1201
1202        MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO;
1203        inode->i_uid = sbi->options.fs_uid;
1204        inode->i_gid = sbi->options.fs_gid;
1205        inode->i_version++;
1206        inode->i_generation = 0;
1207        inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1208        inode->i_op = sbi->dir_ops;
1209        inode->i_fop = &fat_dir_operations;
1210        if (sbi->fat_bits == 32) {
1211                MSDOS_I(inode)->i_start = sbi->root_cluster;
1212                error = fat_calc_dir_size(inode);
1213                if (error < 0)
1214                        return error;
1215        } else {
1216                MSDOS_I(inode)->i_start = 0;
1217                inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1218        }
1219        inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1220                           & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1221        MSDOS_I(inode)->i_logstart = 0;
1222        MSDOS_I(inode)->mmu_private = inode->i_size;
1223
1224        fat_save_attrs(inode, ATTR_DIR);
1225        inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1226        inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1227        set_nlink(inode, fat_subdirs(inode)+2);
1228
1229        return 0;
1230}
1231
1232static unsigned long calc_fat_clusters(struct super_block *sb)
1233{
1234        struct msdos_sb_info *sbi = MSDOS_SB(sb);
1235
1236        /* Divide first to avoid overflow */
1237        if (sbi->fat_bits != 12) {
1238                unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
1239                return ent_per_sec * sbi->fat_length;
1240        }
1241
1242        return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1243}
1244
1245/*
1246 * Read the super block of an MS-DOS FS.
1247 */
1248int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
1249                   void (*setup)(struct super_block *))
1250{
1251        struct inode *root_inode = NULL, *fat_inode = NULL;
1252        struct inode *fsinfo_inode = NULL;
1253        struct buffer_head *bh;
1254        struct fat_boot_sector *b;
1255        struct msdos_sb_info *sbi;
1256        u16 logical_sector_size;
1257        u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1258        int debug;
1259        unsigned int media;
1260        long error;
1261        char buf[50];
1262
1263        /*
1264         * GFP_KERNEL is ok here, because while we do hold the
1265         * supeblock lock, memory pressure can't call back into
1266         * the filesystem, since we're only just about to mount
1267         * it and have no inodes etc active!
1268         */
1269        sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1270        if (!sbi)
1271                return -ENOMEM;
1272        sb->s_fs_info = sbi;
1273
1274        sb->s_flags |= MS_NODIRATIME;
1275        sb->s_magic = MSDOS_SUPER_MAGIC;
1276        sb->s_op = &fat_sops;
1277        sb->s_export_op = &fat_export_ops;
1278        mutex_init(&sbi->nfs_build_inode_lock);
1279        ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1280                             DEFAULT_RATELIMIT_BURST);
1281
1282        error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
1283        if (error)
1284                goto out_fail;
1285
1286        setup(sb); /* flavour-specific stuff that needs options */
1287
1288        error = -EIO;
1289        sb_min_blocksize(sb, 512);
1290        bh = sb_bread(sb, 0);
1291        if (bh == NULL) {
1292                fat_msg(sb, KERN_ERR, "unable to read boot sector");
1293                goto out_fail;
1294        }
1295
1296        b = (struct fat_boot_sector *) bh->b_data;
1297        if (!b->reserved) {
1298                if (!silent)
1299                        fat_msg(sb, KERN_ERR, "bogus number of reserved sectors");
1300                brelse(bh);
1301                goto out_invalid;
1302        }
1303        if (!b->fats) {
1304                if (!silent)
1305                        fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1306                brelse(bh);
1307                goto out_invalid;
1308        }
1309
1310        /*
1311         * Earlier we checked here that b->secs_track and b->head are nonzero,
1312         * but it turns out valid FAT filesystems can have zero there.
1313         */
1314
1315        media = b->media;
1316        if (!fat_valid_media(media)) {
1317                if (!silent)
1318                        fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1319                               media);
1320                brelse(bh);
1321                goto out_invalid;
1322        }
1323        logical_sector_size = get_unaligned_le16(&b->sector_size);
1324        if (!is_power_of_2(logical_sector_size)
1325            || (logical_sector_size < 512)
1326            || (logical_sector_size > 4096)) {
1327                if (!silent)
1328                        fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1329                               logical_sector_size);
1330                brelse(bh);
1331                goto out_invalid;
1332        }
1333        sbi->sec_per_clus = b->sec_per_clus;
1334        if (!is_power_of_2(sbi->sec_per_clus)) {
1335                if (!silent)
1336                        fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1337                               sbi->sec_per_clus);
1338                brelse(bh);
1339                goto out_invalid;
1340        }
1341
1342        if (logical_sector_size < sb->s_blocksize) {
1343                fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1344                       " (logical sector size = %u)", logical_sector_size);
1345                brelse(bh);
1346                goto out_fail;
1347        }
1348        if (logical_sector_size > sb->s_blocksize) {
1349                brelse(bh);
1350
1351                if (!sb_set_blocksize(sb, logical_sector_size)) {
1352                        fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1353                               logical_sector_size);
1354                        goto out_fail;
1355                }
1356                bh = sb_bread(sb, 0);
1357                if (bh == NULL) {
1358                        fat_msg(sb, KERN_ERR, "unable to read boot sector"
1359                               " (logical sector size = %lu)",
1360                               sb->s_blocksize);
1361                        goto out_fail;
1362                }
1363                b = (struct fat_boot_sector *) bh->b_data;
1364        }
1365
1366        mutex_init(&sbi->s_lock);
1367        sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1368        sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1369        sbi->fats = b->fats;
1370        sbi->fat_bits = 0;              /* Don't know yet */
1371        sbi->fat_start = le16_to_cpu(b->reserved);
1372        sbi->fat_length = le16_to_cpu(b->fat_length);
1373        sbi->root_cluster = 0;
1374        sbi->free_clusters = -1;        /* Don't know yet */
1375        sbi->free_clus_valid = 0;
1376        sbi->prev_free = FAT_START_ENT;
1377        sb->s_maxbytes = 0xffffffff;
1378
1379        if (!sbi->fat_length && b->fat32.length) {
1380                struct fat_boot_fsinfo *fsinfo;
1381                struct buffer_head *fsinfo_bh;
1382
1383                /* Must be FAT32 */
1384                sbi->fat_bits = 32;
1385                sbi->fat_length = le32_to_cpu(b->fat32.length);
1386                sbi->root_cluster = le32_to_cpu(b->fat32.root_cluster);
1387
1388                /* MC - if info_sector is 0, don't multiply by 0 */
1389                sbi->fsinfo_sector = le16_to_cpu(b->fat32.info_sector);
1390                if (sbi->fsinfo_sector == 0)
1391                        sbi->fsinfo_sector = 1;
1392
1393                fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1394                if (fsinfo_bh == NULL) {
1395                        fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1396                               " (sector = %lu)", sbi->fsinfo_sector);
1397                        brelse(bh);
1398                        goto out_fail;
1399                }
1400
1401                fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1402                if (!IS_FSINFO(fsinfo)) {
1403                        fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1404                               "0x%08x, 0x%08x (sector = %lu)",
1405                               le32_to_cpu(fsinfo->signature1),
1406                               le32_to_cpu(fsinfo->signature2),
1407                               sbi->fsinfo_sector);
1408                } else {
1409                        if (sbi->options.usefree)
1410                                sbi->free_clus_valid = 1;
1411                        sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1412                        sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1413                }
1414
1415                brelse(fsinfo_bh);
1416        }
1417
1418        /* interpret volume ID as a little endian 32 bit integer */
1419        if (sbi->fat_bits == 32)
1420                sbi->vol_id = (((u32)b->fat32.vol_id[0]) |
1421                                        ((u32)b->fat32.vol_id[1] << 8) |
1422                                        ((u32)b->fat32.vol_id[2] << 16) |
1423                                        ((u32)b->fat32.vol_id[3] << 24));
1424        else /* fat 16 or 12 */
1425                sbi->vol_id = (((u32)b->fat16.vol_id[0]) |
1426                                        ((u32)b->fat16.vol_id[1] << 8) |
1427                                        ((u32)b->fat16.vol_id[2] << 16) |
1428                                        ((u32)b->fat16.vol_id[3] << 24));
1429
1430        sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1431        sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1432
1433        sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1434        sbi->dir_entries = get_unaligned_le16(&b->dir_entries);
1435        if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1436                if (!silent)
1437                        fat_msg(sb, KERN_ERR, "bogus directory-entries per block"
1438                               " (%u)", sbi->dir_entries);
1439                brelse(bh);
1440                goto out_invalid;
1441        }
1442
1443        rootdir_sectors = sbi->dir_entries
1444                * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1445        sbi->data_start = sbi->dir_start + rootdir_sectors;
1446        total_sectors = get_unaligned_le16(&b->sectors);
1447        if (total_sectors == 0)
1448                total_sectors = le32_to_cpu(b->total_sect);
1449
1450        total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1451
1452        if (sbi->fat_bits != 32)
1453                sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1454
1455        /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
1456        if (sbi->fat_bits == 32)
1457                sbi->dirty = b->fat32.state & FAT_STATE_DIRTY;
1458        else /* fat 16 or 12 */
1459                sbi->dirty = b->fat16.state & FAT_STATE_DIRTY;
1460
1461        /* check that FAT table does not overflow */
1462        fat_clusters = calc_fat_clusters(sb);
1463        total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1464        if (total_clusters > MAX_FAT(sb)) {
1465                if (!silent)
1466                        fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1467                               total_clusters);
1468                brelse(bh);
1469                goto out_invalid;
1470        }
1471
1472        sbi->max_cluster = total_clusters + FAT_START_ENT;
1473        /* check the free_clusters, it's not necessarily correct */
1474        if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1475                sbi->free_clusters = -1;
1476        /* check the prev_free, it's not necessarily correct */
1477        sbi->prev_free %= sbi->max_cluster;
1478        if (sbi->prev_free < FAT_START_ENT)
1479                sbi->prev_free = FAT_START_ENT;
1480
1481        brelse(bh);
1482
1483        /* set up enough so that it can read an inode */
1484        fat_hash_init(sb);
1485        dir_hash_init(sb);
1486        fat_ent_access_init(sb);
1487
1488        /*
1489         * The low byte of FAT's first entry must have same value with
1490         * media-field.  But in real world, too many devices is
1491         * writing wrong value.  So, removed that validity check.
1492         *
1493         * if (FAT_FIRST_ENT(sb, media) != first)
1494         */
1495
1496        error = -EINVAL;
1497        sprintf(buf, "cp%d", sbi->options.codepage);
1498        sbi->nls_disk = load_nls(buf);
1499        if (!sbi->nls_disk) {
1500                fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1501                goto out_fail;
1502        }
1503
1504        /* FIXME: utf8 is using iocharset for upper/lower conversion */
1505        if (sbi->options.isvfat) {
1506                sbi->nls_io = load_nls(sbi->options.iocharset);
1507                if (!sbi->nls_io) {
1508                        fat_msg(sb, KERN_ERR, "IO charset %s not found",
1509                               sbi->options.iocharset);
1510                        goto out_fail;
1511                }
1512        }
1513
1514        error = -ENOMEM;
1515        fat_inode = new_inode(sb);
1516        if (!fat_inode)
1517                goto out_fail;
1518        MSDOS_I(fat_inode)->i_pos = 0;
1519        sbi->fat_inode = fat_inode;
1520
1521        fsinfo_inode = new_inode(sb);
1522        if (!fsinfo_inode)
1523                goto out_fail;
1524        fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1525        sbi->fsinfo_inode = fsinfo_inode;
1526        insert_inode_hash(fsinfo_inode);
1527
1528        root_inode = new_inode(sb);
1529        if (!root_inode)
1530                goto out_fail;
1531        root_inode->i_ino = MSDOS_ROOT_INO;
1532        root_inode->i_version = 1;
1533        error = fat_read_root(root_inode);
1534        if (error < 0) {
1535                iput(root_inode);
1536                goto out_fail;
1537        }
1538        error = -ENOMEM;
1539        insert_inode_hash(root_inode);
1540        fat_attach(root_inode, 0);
1541        sb->s_root = d_make_root(root_inode);
1542        if (!sb->s_root) {
1543                fat_msg(sb, KERN_ERR, "get root inode failed");
1544                goto out_fail;
1545        }
1546
1547        if (sbi->options.discard) {
1548                struct request_queue *q = bdev_get_queue(sb->s_bdev);
1549                if (!blk_queue_discard(q))
1550                        fat_msg(sb, KERN_WARNING,
1551                                        "mounting with \"discard\" option, but "
1552                                        "the device does not support discard");
1553        }
1554
1555        fat_set_state(sb, 1, 0);
1556        return 0;
1557
1558out_invalid:
1559        error = -EINVAL;
1560        if (!silent)
1561                fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1562
1563out_fail:
1564        if (fsinfo_inode)
1565                iput(fsinfo_inode);
1566        if (fat_inode)
1567                iput(fat_inode);
1568        unload_nls(sbi->nls_io);
1569        unload_nls(sbi->nls_disk);
1570        if (sbi->options.iocharset != fat_default_iocharset)
1571                kfree(sbi->options.iocharset);
1572        sb->s_fs_info = NULL;
1573        kfree(sbi);
1574        return error;
1575}
1576
1577EXPORT_SYMBOL_GPL(fat_fill_super);
1578
1579/*
1580 * helper function for fat_flush_inodes.  This writes both the inode
1581 * and the file data blocks, waiting for in flight data blocks before
1582 * the start of the call.  It does not wait for any io started
1583 * during the call
1584 */
1585static int writeback_inode(struct inode *inode)
1586{
1587
1588        int ret;
1589
1590        /* if we used wait=1, sync_inode_metadata waits for the io for the
1591        * inode to finish.  So wait=0 is sent down to sync_inode_metadata
1592        * and filemap_fdatawrite is used for the data blocks
1593        */
1594        ret = sync_inode_metadata(inode, 0);
1595        if (!ret)
1596                ret = filemap_fdatawrite(inode->i_mapping);
1597        return ret;
1598}
1599
1600/*
1601 * write data and metadata corresponding to i1 and i2.  The io is
1602 * started but we do not wait for any of it to finish.
1603 *
1604 * filemap_flush is used for the block device, so if there is a dirty
1605 * page for a block already in flight, we will not wait and start the
1606 * io over again
1607 */
1608int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1609{
1610        int ret = 0;
1611        if (!MSDOS_SB(sb)->options.flush)
1612                return 0;
1613        if (i1)
1614                ret = writeback_inode(i1);
1615        if (!ret && i2)
1616                ret = writeback_inode(i2);
1617        if (!ret) {
1618                struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1619                ret = filemap_flush(mapping);
1620        }
1621        return ret;
1622}
1623EXPORT_SYMBOL_GPL(fat_flush_inodes);
1624
1625static int __init init_fat_fs(void)
1626{
1627        int err;
1628
1629        err = fat_cache_init();
1630        if (err)
1631                return err;
1632
1633        err = fat_init_inodecache();
1634        if (err)
1635                goto failed;
1636
1637        return 0;
1638
1639failed:
1640        fat_cache_destroy();
1641        return err;
1642}
1643
1644static void __exit exit_fat_fs(void)
1645{
1646        fat_cache_destroy();
1647        fat_destroy_inodecache();
1648}
1649
1650module_init(init_fat_fs)
1651module_exit(exit_fat_fs)
1652
1653MODULE_LICENSE("GPL");
1654
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